Blood film

Keywords: Peripheral smear, Film, BF

Specimen:

5 mL blood in EDTA.

2 mL blood in special paediatric EDTA tube.

Method:

Film spread, fixed, stained and examined by microscopy.

Application:

Evaluation of changes in numbers or morphology of red cells, white cells and platelets.

Blood film examination clarifies abnormalities detected by automated haematology instruments and guides further investigation.

A blood film examination may not be reviewed routinely when all automated analyser full blood examination parameters are normal, however a specific request for film review can be made when ordering a full blood examination.

Interpretation:

Microscopic examination reveals abnormal cells;
detects and provides an interpretation of abnormal red cell, white cell and platelet morphology; 
detects intra and extra erythrocytic parasites;
detects artefacts causing counting errors on automated instruments; and
provides an assessment of polychromasia (reflecting reticulocytosis), rouleaux and red cell agglutination.

Reference:

Bain BJ. Blood cells: a practical guide. Fourth edition. Oxford: Blackwell Publishing, 2007.